Entropy: Order and Disorder
by Sigridhr
Summary: In thermodynamics, entropy defines the amount of order, disorder and chaos in a thermodynamic system. In Darcy, it defines how much of her is still left behind. Loki magically enhances Darcy to help expedite the building of a Bifröst. When things start going wrong, he realises just how much she's come to mean to him. COMPLETE.
1. Nascence

**Entropy (Order and Disorder)**

_In thermodynamics, entropy defines the amount of order, disorder and chaos in a thermodynamic system. In Darcy, it defines how much of her is still left behind._

**Beta:** A huge thank you to acadecian, who helped turn this into something presentable.

**Pairing: **Loki/Darcy

**Rating:** M (ye be warned).

**Warnings:** Tony Stark, profanity, sexy times, magic parading as science, Wikipedia parading as research, Darcy being a BAMF, and may cause flashbacks to _Flowers for Algernon_ in some readers.

**Notes:** Couple of things you should know –

(1) This fic should properly be titled "How Not To Math". (Math is just magic that I don't understand yet, clearly). I'm not a math or physics major, sadly, so any science-y errors are mine, and corrections will be much appreciated.

(2) This is heavily inspired by the novel _Flowers for Algernon_, and draws its overarching plot points from that work. There is no need to have read the novel to follow this story, however.

(3) This is set after the end of the Thor movie, and is AU for the Avengers film. Some Avengers characters turn up, however. There is also a single line taken from the Avengers film, which I suppose could be considered a small spoiler of sorts.

(4) This is the first thing I've written in over three years. I would say go easy on me, but, actually, tear it to shreds! I'll learn more that way. :) The story is complete – updates will happen every two days. Enjoy!

**Chapter 1: Nascence**

* * *

Darcy was just finishing locking up the lab for the night when he grabbed her, materializing out of the shadows like a ghost and covering her mouth with his long pale fingers before she could so much as scream. She dropped her keys when he dragged her back in through the door, shutting it with a bang behind her. Despite the panic clouding her thoughts she hoped desperately that Jane had heard the door slam from her trailer and would come out to investigate. Then again, she thought, feeling the way his arm was clamped around her like a vice, his fingers covering her mouth hard enough to bruise, and his breath, warm against the side of her face, sent shivers of revulsion down her spine, it was probably best if Jane stayed far, far away.

He spun her around so quickly she felt suddenly dizzy and pushed her back into Jane's desk chair, his hand still clamped over her mouth. She had absolutely no idea who this man was, but, oh boy, was she convinced he was _batshit crazy_. She'd never seen him before, and she wondered if he was with SHIELD, based on the well-tailored suit he was sporting. Then she wondered if she was about to disappear into the depths of some creepy research facility, or, worse, be shot and stuffed in a car trunk, and never be seen or heard from again. This did little to quell the absolute terror she felt running through her veins like ice.

"I will remove my hand if you agree not to scream," he said in a low, even voice.

She nodded, her eyes wide in terror, and he slowly removed his hand.

Darcy took a shaky breath in, and then screamed as loud as she could.

He hissed, bending forward and covering her mouth again in a single, fluid motion that reminded her of a snake striking its prey. His eyes narrowed in fury as his face hovered close to hers. "That," he said slowly, though with an underlying menace that was as clear as if he were shouting, "was unwise."

She bit down on his finger as hard as she could manage, and kicked the closest part of him she could reach. She tried frantically to get to her bag and pull out her taser.

He snarled in fury and gripped her shoulder so tightly it felt like she was being squeezed in a vice, effectively pinning her to the seat.

"Stop," he said, firmly.

"Let me go!" She kept kicking at his knees, but he seemed not to notice.

He sighed, sounding for all the world as if she were utterly wasting his time, and stepped back. Before she could scramble out of the chair she felt tight ropes materialize and wind themselves around her, binding her firmly to the chair.

"I hope your position is clear to you," he said flatly. "I have no desire to waste any more time with your pointless theatrics."

"Who are you?" Darcy asked, her voice wavering more than she wanted it to. He looked at her blankly in response.

"My friend probably heard all that, you know," she continued when it became clear that he was not about to speak. "The police are probably on their way. So why don't you just let me go, and you can go on your merry way, and nobody gets hurt, ok?"

"Unlikely," he replied. "I have enchanted the area so that sound will not travel. Your companion, _Jane Foster_–" Darcy definitely did not like the way he sneered Jane's name with clear loathing "—remains blissfully unaware of my presence here."

"'Enchanted'?" Darcy said. "Got magic powers there, Dumbledore?" As soon as the words left her mouth she regretted them, expecting him to lash out but he just looked at her with a mixture of puzzlement and disdain. Then he looked pointedly at the ropes that bound her and sneered.

"That much," he said sarcastically, "I had thought was obvious."

She blinked. _Right_. Magic powers. What the _actual fuck_.

"I require your assistance," he said, leaning almost casually against the table. "There is no one on Midgard with sufficient skill or intelligence to accomplish what I need, particularly within the short amount of time I have available. You will aid me in the construction of a Bifröst."

"Oh, shit," she said, the sheer enormity of the trouble she was in beginning to dawn on her. "Oh shit, shit, shit. You're one of them – from Asgard. Like Thor."

At them mention of Thor's name, his features contorted in fury, and he made an aborted move towards her as if he'd been about to strike her but had stopped himself at the last minute. "Do not mention that name," he hissed.

"Sorry! Sorry." She was not even a little bit ashamed to admit she was cowering in her chair. She'd nearly peed herself in terror.

He stood up, and straightened his cuffs with an air of imposed nonchalance. "You will assist me in the construction of a Bifröst," he said again. "You do not have the intelligence to manage such a feat on your own, so I will expand your capacity to learn and understand."

"You're going to make me _smarter_?" she said incredulously.

"_Smarter_," he said, "is a relative term. And in your case there is ample room for improvement."

"You've already scared the crap out of me and tied me down, there's no need to be insulting," she muttered.

He blinked in surprise and took a step back. "You have _defecated_?"

"What? No! It's an expression, you weirdo."

He scowled at that. "Choose your words wisely, mortal. I have chosen you because you are expendable – do not make the mistake of thinking that I will not replace you should you fail to meet my needs."

Darcy scowled in reply, but bit down hard on the snarky retort she was thinking. The corner of his lip curled up in amusement at that. "Well, well, it can be taught."

"Now," he said, holding both his hands up in front of her face, "keep silent and still. This is delicate work, and if your squirming causes me to accidentally eradicate your mind leaving you nothing but an empty shell, it will be tremendously inconvenient for me."

"Thrilled to hear it," Darcy muttered, holding as still as she could despite every instinct in her body screaming at her to fight him off. She had no way of knowing whether moving would really leave her brain dead, but she wasn't prepared to find out.

His fingers brushed her temples with surprising gentleness, though it did little to stop the shudder of dislike she felt at the thought that he was touching her at all. She felt his hands splay out on her skull, and a strange tingling sensation, like something was crawling all over her head. She clenched her teeth so hard she could feel the muscles of her jaw spasm and her breathing was loud and shallow in the quiet lab. Suddenly, his hands pressed down hard, each finger like a blinding spot of white-hot pain, and she was screaming, her eyes clenched tightly shut as she thought her skull would split at the seams. Then suddenly it was still again, save for the sound of her own ragged, shuddering sobs. Her head felt swollen and foreign, like she was heavily medicated.

When she finally looked up, he was staring down at her, his brows slightly furrowed. "You are more fragile than I had anticipated," he said, without inflection. "I am not certain how effectively the change has taken hold. It was somewhat hard to concentrate through all the screaming."

"I'm _so _sorry," Darcy sneered, all sense of self-preservation seemingly gone.

"Perhaps you will be," he replied. "But it makes no difference to me, as long as you are capable of the work I require."

He pulled the chair on the far side of the desk across the floor towards him and it made a horrible scraping sound on the linoleum. He spun it around and sat, facing her, leaning forward to rest his elbows on his knees, his legs slightly spread.

"I will instruct you on the magic necessary to construct a working Bifröst. Ordinarily a mortal mind would be much too small to comprehend the workings of the universe, much less navigate them, but, if my adjustments have taken hold, you should be able to manage well enough to suit my needs. I will provide you with instruction on the relevant theory, and you will relay that theory carefully, as to avoid suspicion, to Miss _Foster_–" again, he sneered her name as if even saying it left a vile taste on his tongue "—whose work will serve as an adequate starting point. You will then build the Bifröst and bring it to me, destroying all notes and materials that would enable other mortals to replicate it."

She stared, owlishly at him. "Uh, Jane's never gonna believe that I know anything about physics."

He stared at her for a very long, very tense moment. "You are her assistant?"

"Uh, yeah."

"Then you will assist her, and, by extension me," he said slowly, enunciating clearly to emphasize the fact that he thought she was a complete moron.

"Yeah, but I'm not a scientist. I file things, I make coffee, I drive the van, I do what I'm told – I don't actually do any of the science."

He sat back in his chair and made an exasperated noise. "Well then," he said, in what Darcy had now dubbed his 'I'm rapidly losing my patience' tone, "you will simply have to _learn_. That was, after all, the point." He looked her up and down, seeming perturbed. "I'm beginning to think that I have had no effect at all. You should not still be this much of an imbecile."

"Hey –"

"Silence," he said, and the word hit her almost as if he'd actually slapped her. "Now, I have reviewed the work as it stands already. It is evident that your kind has not even a rudimentary understanding of the ways of the universe. Your work as it stands now would rely on atmospheric disturbances to generate the power necessary to open the bridge. This will not be successful – it is an insufficient, unstable and unreliable source of power."

"The paths that traverse the universe already exist," he said, sitting back in his chair, and, although she was still quite a bit frightened and still tied to her chair, she couldn't help but be a bit enraptured by the way he spoke.

"Once you are on the correct path, following it is simple: it is finding the path that is dangerous. It is not only energy that is required, but _intent_. The centre of the Bifröst is not a machine, but a mind – yours, should I succeed – that guides the footsteps of its travelers along the correct bridge."

"You need me to run the machine?" she asked, shakily.

He grinned, and in the dark lab, his features outlined sharply by the pale glow of the streetlights outside, she thought he looked positively lupine. "Precisely."

"How?"

"First we must build it," he replied. "It still requires a great deal of energy to open such a door, and that energy requires a harness. Then, I will teach you to _see._"

"See what?"

"Yggdrasil," he said. "To see the shape of the universe, and to traverse it, mould it with your thoughts alone. Your mind will touch stars that none of your kind ever have, nor ever will, see. I have given you an extraordinary gift – though it was done only out of necessity – there are no others like you, now."

She swallowed thickly, feeling like she was missing a key to most of the conversation. But she'd followed the gist of it, and the implications of what he'd just done to her were terrifying.

"Are you telling me I'm no longer human?" She felt bile rise in her throat at the thought, and she swallowed, willing herself desperately not to throw up.

"I think it is a tremendous improvement," he said, glibly.

"Can you turn me back?" she asked, desperation crawling inside her like a caged animal. "When I'm done being your pilot, or whatever, will you fix me?"

"Perhaps," he replied.

Suddenly, the bonds around her arms and legs went slack and then disappeared. Her hands and feet felt completely numb, and she rolled her wrists and ankles, wincing as she felt the beginnings of pins and needles.

"I have made it impossible for you to speak of my presence to anyone, so I suggest you do not try," he said, rising from his seat and returning the chair to where he'd found it. "I have research of my own to undertake. I will return to you to provide further instruction when it is complete."

He looked at her once more, assessing her. "We will know soon enough if there is any change."

He reached towards her, and reacting on instinct she shrunk back and raised her arms. He made a tut-ting sound and brushed her arms aside, laying his hands gently on her jaw. She clenched her teeth, her breathing shallow and loud, and he chuckled. She felt a strange, tingling warmth spread from his fingers and across her jaw.

"To prevent bruising," he said by way of explanation. "And to avoid awkward questions."

He stood, not bothering to attend to the bruises that were already forming on her shoulders and arms.

"Wait," she said, moving to stand and then thinking better of it as her still limp legs nearly gave out under her. He looked singularly unimpressed as she flopped back into her chair. "I don't even know who you are."

Something in him changed – he stood slightly taller, and suddenly, despite the suit and the light dusting of sand on his shoes from the New Mexico desert, he looked every bit as imposing, as foreign and _alien_as Thor had in his armour, and she felt tremendously small.

"I am Loki, of Asgard," he said, "and I am burdened with glorious purpose."

The door slammed again as he left, and Darcy sank off the chair and onto the floor.

* * *

**Footnotes:**

(1) Loki's line about being 'burdened with glorious purpose' comes from the Avengers movie, and is, thus, not mine.


	2. Confirmation

**Notes:**A huge thank you to everyone who's read, favourited, subscribed to and reviewed this story! Just a quick note - I'll be down in London for the weekend so there is a small possibility that the next chapter might not be updated in time if I can't get access to internet. Unlikely - but consider yourself forewarned.

**Chapter 2: Confirmation**

* * *

True to his word, any attempts to tell Jane or Erik about her late-night visitor just resulted in the words getting caught in her throat rendering her literally unable to speak. She didn't feel much different, despite Loki's promises that he had made her into something _else_, although every time she thought about it she felt physically ill and a bit like crawling out of her skin.

She'd tried writing it down, but it seemed Loki had prepared for that particular loophole. Any attempt to write anything about him, or that she'd seen him, resulted in her scribbling what appeared to be knitting patterns on her notepad. "Loki did something to my brain last night" came out as "knit one, purl two, for ten rows, then knit two, purl one for another ten."

In frustration she wrote "Loki is a dick" in bold letters in the centre of her notepad. Instead, it read "Darcy is a dick." She ripped the page out and threw it in the trash, deciding it wasn't worth playing the written equivalent of 'stop hitting yourself' with a Norse God.

Instead, she made coffee, passing a mug to Jane (her third of the morning – _addiction _was too mild a word for Jane's relationship to coffee) and another to Erik. She sipped her own as she transcribed Jane's atmospheric data records to the Excel spreadsheet.

Erik and Jane were arguing about equations again. She turned her iPod up.

…

He was standing outside the lab as she locked up again that evening.

She clenched her keys between her fingers and made a fist. "Please don't drag me inside and tie me to a chair again," she said, hoping she didn't look as terrified as she felt.

He leant casually up against the door. "I have no intention of tying you to anything."

"Good," she said. "Because that's rude."

"So is biting and kicking," he replied. "Have you made any progress?"

"On what?" she asked.

He sighed and looked very put upon. "Evidently not," he said and walked away.

"Bye, then," she shouted after him. "Weirdo," she added under her breath.

…

She tried looking Loki up on the internet and showing the webpage to Jane and Erik.

"Why am I reading the Wikipedia entry on Wile E. Coyote?" Erik asked.

Darcy groaned and let her head fall to the table with a satisfying 'thunk'.

…

It was Thursday, and she'd transcribed all of Jane's notes in under three hours. She rolled her shoulders, frowning a bit as she double-checked that she'd actually copied out everything. She skimmed the file, absentmindedly reordering the pages. Looking back at the Word document, she started copy-pasting sections to reorganize them based on content, grouping the equations together until the notes read more like a coherent narrative than Jane's haphazard scribblings which tended to skip around as she worked out bits and pieces.

Darcy let out a long breath as she stared at her work. She didn't know what any of the equations meant, but she'd recognized patterns, grouping like with like.

She shut down the computer, poured the rest of her coffee down the sink and left for home without saying goodbye.

…

"Are you sure you're ok?" Jane asked, over pancakes at Isabella's. "You seem… preoccupied."

Darcy shrugged. "Just tired, I guess." She took a bite of her pancake. "Have you considered using extra-spatial dimensions to balance that equation you were working on last night?"

Jane gave her a long, perplexed look over her coffee cup. "Yeah," she said at last. "You're totally normal."

"Just taking an interest," Darcy said, shoveling more pancakes into her mouth.

…

When she walked in the door that evening, Loki was sitting gingerly on the edge of her bed, looking slightly disgusted with the unkempt state of her small studio apartment. Somehow seeing him looking so out of sorts made him significantly less frightening.

"Make yourself at home," she said sarcastically, tossing her keys onto the desk and kicking a dirty pair of trackpants under the bed as she made her way to the fridge. "Why do you wear suits all the time, anyway? It's like 100 degrees in the shade outside."

"Camouflage," he said. "People respect those in business attire, but its nondescript enough to not pin me down to a particular profession."

"And I'll bet you have knobbly knees," said Darcy. He glared at her and pointedly changed the subject.

"Have you made any progress?" he asked, standing and brushing off his lapels as if the mere act of sitting in her slovenly, one-room apartment had somehow dirtied him.

"Jane's certain that exotic matter is the key to identifying Einstein-Rosen bridges – she's hoping the particle data results we have from the last couple times the Bifröst opened will give us a hint as to how to locate the stuff." She rummaged around in the back of her mini fridge, pulling out the orange juice and then slammed the door shut with her hip as she pulled a glass out of the cupboard. "Juice?"

"No," he said disdainfully. "Your intellect seems to have improved, at any rate."

"Yeah," Darcy said. "I read the entirety of the Prose Edda in about an hour last night. Is any of that stuff actually true?"

"The truth is a point of view. There is no such thing as absolute truth," he said, absently. "However, much of what is written is not as I remember it, and a great deal more is complete fabrication."

"And the bit with the horse, Svaðilfari?" she asked, looking as innocent as she could manage without snickering.

He glared at her and reached across the table that she had converted into a desk which delineated the eating space from the sleeping space in her apartment, and stole her juice. "Your pronunciation needs work," he said.

"I'll take that as a yes," she said, pouring herself a second glass. He stole that one too.

"Don't be spiteful."

"I could still kill you." He placed both empty glasses in her sink.

"But you won't," she said, sitting on the edge of the desk. "Because whatever you did is working, and you need my help."

"So long as you remain useful," he said, leaving the implied threat to hang in the air between them.

"I read you loud and clear," she replied. "Would you like some food to go with all the juice you so heartlessly stole from me?"

…

They were in Isabella's again, and Darcy could hear her speaking in rapid Spanish to one of the other regulars about how expensive eggs were getting. It was ten minutes of absent-minded eavesdropping before she realised that she hadn't been able to speak Spanish before.

She wasn't catching every word – just the gist of the conversation. Every half-remembered word from the Spanish lessons she'd had in grade school had apparently become active vocabulary.

When she got home she downloaded a learn Spanish course online and picked up a copy of _Harry Potter y la piedra filosofal_ from the library. By the end of the following week she'd finished _Don Quixote_ and the _Romancero Gitano_in the original Spanish.

She dreamt of walking empty paths through the stars, and woke up crying.

…

_I'm not entirely certain that I am _myself_ anymore. What frightens me most is that something integral to the person that I am has changed. Even so, I'm not certain that I would go back if I were given the choice._

…

Loki started turning up every night, and they had long, meandering conversations about the universe. He spoke without any scientific precision, instead with a sense of old-world mysticism, but she was able to follow along well enough, and her mind began to slowly form links with what she knew about the work that Jane was doing – reconciling his descriptions with her equations.

His hands all but danced as he talked, and she could almost see a model of the universe, paths like winding branches, spread in the air between them as he talked. Her heart pounded in her ears like the sea and she felt like blinds she hadn't even known were there had been drawn back on the world. She told him as much.

Loki just smiled knowingly, and looked content enough with her progress. "Patience," he said. "You cannot reach the top of the tree to see above the canopy without first climbing the lower branches."

"I hate metaphors," she said.

…

She was possessed with a fevered desire to _know things_. She spent her evenings reading up on the theory behind Jane's work. She read recent issues of the _Journal of Modern Physics, _the _Physical Review_ and the _Journal of Math and Physics_. The equations jumped off the page at her, translating themselves into matter in her mind's eye, which she manipulated. She had constant questions – everything she read lead to more questions, more answers, more thoughts, more _knowledge_.

She started keeping a notebook, with her own equations, and copied snippets of Jane's. The first time she balanced one of Jane's equations for her she felt pleased with herself, and a bit sick at the thought that she didn't really _need_ Jane anymore, despite the fact that she still thought of it as _Jane's work_.

…

"What's happened to you?" Jane asked her, looking slightly frantic. "Two months ago you had trouble even _transcribing _my notes, now you've balanced my equations? Do you even understand what you've done here?"

Erik watched quietly from the other side of the lab, silent and calculating.

"What's gotten into you?" Jane demanded, her voice tinged with a hint of hysteria. "This is _my work_."

"I'm _helping_," Darcy insisted.

"I don't know _what _you're doing," Jane said. "But it wasn't what I hired you for."

"You hired me to make coffee and type up notes. This is more useful," Darcy said. "Don't you want Thor back?"

But they both knew the truth, though it hung heavy and silent in the air. This was and always had been Jane's life's work, until the scales had tipped and it had started to become _Darcy's _discovery.

She tried to explain, to tell her that she'd been changed, that Loki had done this to her against her will, that she wasn't stealing anything she just _needed to understand_ because she could almost _see_ it and inactivity clawed at her like an itch. That her mind took in information like a sponge and she craved it – that learning had become something she enjoyed, something she needed. That she alone, perhaps, had the potential to _truly_ understand it all, and that it was all within her grasp. That she was becoming something _else_, and that it scared her as much as it excited her.

_There are no others like you, now._

The words wouldn't come.

"I feel like I don't know you anymore," Jane said.

The next time she and Erik went to Isabella's for breakfast, Darcy wasn't invited.

…

She was reading articles from _Documenta Mathematica_in German when Loki walked in her front door.

He glanced at the text over her shoulder and snorted derisively.

"We can't all use metaphors to understand the universe," she said in reply. "Equations are just a means of notation to explain how things work."

"Then how are they not metaphors?" he asked as he helped himself to food from her fridge. "Although they are as inelegant as your species."

"Be nice," she said.

"I," he replied, looking ludicrously out of place as he made himself a sandwich in her messy kitchen. "Am not _nice_."

She rolled her eyes and kept reading.

…

"If the Bifröst is to work, it must be correctly guided by your mind. Then you can redirect the energy to open the door, and propel me through it on the correct path."

"How do I find the path?" She was cross-legged on her bed, notes, printed articles from physics journals, novels and sketches strewn haphazardly across the bedspread and the floor. Loki had cleared a space for himself meticulously on the corner of her bed. His disgruntled expression reminded her of a cat.

"You must know where you're going. You must be able to see both the end and the beginning – your mind must walk the paths before my feet do."

"That's not much help," she said.

"It will be, in time."

…

"Why did you pick me?" she asked one evening as he traced patterns of Yggdrasil with his fingers and her mind translated metaphor into matter.

He blinked and his hands stilled, hovering in the air like a marionette. "You were expendable," he said, dropping his hands. "And beneath the notice of those who would pose a threat to me."

Her expression twisted in disgruntlement.

"If you were fishing for compliments, you had best look elsewhere."

"I wasn't," she said. "I just need to understand. I've learned so much about the universe, but I still know so little about you."

His eyebrows raised slightly. "It is not necessary to know anything about me to do what I've asked."

"And if I don't want to do as you've asked?"

His postured changed, he stiffened and his expression closed down as if a shutter had dropped across his face. "I am more than capable of persuading you."

"I know," she said, picking at a loose thread on her jeans. "But I also know you told Thor his father was dead when he wasn't, and then sent that destroyer thing to kill him, and us, and now you're here and trying to go back to Asgard, and Thor conspicuously _isn't_here and I'm not sure I wouldn't rather be dead than be complicit in whatever it is you're planning."

"You tread on very thin ground, _girl_," he hissed furiously.

"And yet you sit around in my horrible apartment and make sandwiches, and we talk about the world. I don't believe that you've only told me things I need to know in order to work the Bifröst because I learned Latin in three days so I'm fairly certain you could just swoop in when we've built this thing and give me a crash course, but instead you keep turning up and raiding my fridge and spending time with me. And I think you get something more out of it than just someone to help you get home, or whatever it is you're doing. But if you do actually enjoy talking to me, why have you never even asked my _name_?"

He looked a bit dumbstruck, like he was unsure whether he was furious or amused.

"It's Darcy, by the way," she said. "And I've enjoyed our conversations too."

He stood up and stalked out of her room, slamming the door so hard that the wood of the frame actually cracked around the hinges as he left.

* * *

**Footnotes:**

(1) Svaðilfari, for anyone who is unaware, is the male horse which Loki lures away by shape shifting into a mare, that fathers Loki's first child: the eight-legged horse Sleipnir Odin rides in the film. So, basically, Darcy just asked him if he'd ever given birth to a horse. You're welcome.


	3. Apogee

**Notes:** I'm really sorry, as I'm about to spam everyone who has me on author/story alert. I'm going to be in London longer than I thought, and I won't have reliable internet access after all - so, since this story is complete, I thought I'd post the remaining chapters now rather than put it on hiatus for the week. Unfortunately, I won't be able to respond to reviews right away, but please know that they are very much appreciated.

**Chapter 3: Apogee**

* * *

Erik placed a stapled booklet on the desk in front of her when she turned up to work that morning. She blinked at it in surprise.

"It's an IQ test," he said unnecessarily. "You've got two hours – I'll time you."

She finished it in less than one.

He looked wary, though a bit surprised, when she handed it to him.

"What'd I get?" she asked, when he finished checking the answers.

"190," he said, looking at her cautiously, like she was a wild animal and he wasn't sure what she'd do next.

Jane picked up her test and looked through it, a mixture of concerned and frustrated. "Darcy," she said. "What's happened to you?"

All she could do was shake her head helplessly. "I can't say," she said, wishing desperately it wasn't quite so true.

"I think we need to call SHIELD," Erik said. "This… isn't normal."

Jane nodded, giving her that same wary look.

…

"You're back," she said stupidly when she walked in to find Loki sitting at her desk, reading her Spanish copy of Harry Potter. "And you speak Spanish?"

"I speak All-speak," he said without looking up.

"Can I learn that?" she asked, crossing the room to put the groceries she was carrying away.

He gave her a calculating look. "Possibly," he said.

"Cool beans."

…

Tony Stark breezed into their lab like he owned it the following Tuesday, and he immediately shut the doors and brought in an air conditioner.

"I don't know how you people work in this hell hole," he said.

"Stubborn determination and a near-lethal caffeine intake, mostly," Darcy said.

"I hope you mean _iced _coffee," he said, before thumbing through Jane's carefully organized piles of notes and equations, messing everything up and sending her into a fit of near apoplexy which took him by surprise, though he apparently liked her work well enough to laugh it off – but not enough to reorganize it.

"So I hear you're a genius," he said to Darcy as he leaned on the counter next to her. "Aren't many genius bombshells out there – and then Fury told me there were two out here in middle of fucking nowhere New Mexico. I wondered why it took him so damn long to extend an invitation."

"I expect he had our best interests at heart," Darcy said, pinching a packet of sugar between her finger and thumb and shaking it before ripping it open.

"Dr. Foster I'd heard about," he continued, as she fixed her coffee. "Read some of her papers – weird stuff, but, apparently, if Coulson's reports are to believed, true. But you – file says you're a Poli Sci major who suddenly developed a firm grasp of astrophysics and has an IQ higher than Stephen Hawking?"

She turned to go, but he stepped carefully into her path, stopping her in her tracks. "So, I'm willing to bet this sudden genius is a recent development. Your grades were good, but not stellar in high school and university, and your grasp of physics by all accounts tenuous until about two months ago. So, darling, what's changed?"

"I can't say," she said.

He stared at her for a very long moment before stepping out of her way. "Can't you, now?" he said, almost to himself. "Interesting."

She blinked, and then smiled widely at him, and his eyebrows almost disappeared into his hairline.

…

"So," said Agent Coulson, sitting with an air of affect nonchalance across the table from her. "Stark seems to think that when you say that you can't say what happened to you, you literally _cannot_say. Is that the case?"

She nodded.

"Great," he said sarcastically. "So I guess we'll just have to play twenty questions until we guess what's going on here. But we are correct in assuming that _something _has happened to you, Miss Lewis?"

She found she couldn't nod to that one, so she just sat still hoping he'd take that as a yes.

He sighed. "I really hate this town."

"The library is utter crap," she agreed.

"If you can't tell us, then can you at least write it down?" He pushed a pad of paper and a pen over to her.

She smiled sardonically. "I tried that," she said. She tried to write down Loki's name and a brief description of what he'd done. She pushed the pad back over to Coulson.

"Knit ten rounds of K1P2 ribbing," he read. "Is this a joke?"

"I'm pretty sure it's a pattern for a hat," she said. "He's got a terrible sense of humour."

"Who?" Coulson pressed.

She shrugged helplessly.

…

"Are you firing me?" she asked, standing as tall as she could and glaring levelly at Agent Coulson, who stood passively, but firmly, between her and the door. "Because I'm pretty sure that's not your decision."

"No," he said. "We're assessing the situation."

Tony stuck his head out the door. "Get in, Lewis, we're losing daylight."

"Miss Lewis isn't cleared for research," Coulson said. "She's been temporarily suspended."

"Bullshit," said Tony. "She's the best damn mind working on this project – except me, of course – we need her."

"Yes," Coulson replied calmly. "But it's clear she's been compromised somehow, and I'm willing to wager someone else needs her too. I'm not playing into some unknown's hands." He turned to look at Darcy. "Especially since Miss Lewis is unwilling to talk."

"Unable," she corrected.

"Yes, yes," said Tony. "But we _need_ her. What makes you so sure we won't be playing into someone's hands if we complete this thing in a year instead of this month? Then we'll have wasted everyone's time and money – worse, wasted _my time _– and for what?"

"Thor will be able to help," Darcy added. "If we can get him back."

"Are we dealing with another Asgardian?" Coulson asked sharply.

"Thor will help," she said.

He sighed, and stepped aside. "I suspect I may come to regret this."

…

"We're getting close, now, I think," she said. She and Loki were eating bowtie pasta out of bowls side by side on the bed. His was decorated with little cartoon pigs, and he'd sneered in displeasure when she'd handed it to him. She didn't care – the cow bowl was hers. Cows were much cooler than pigs.

"Can I go with you to Asgard?" she asked, poking at her pasta with her fork.

"No," he said. "If one could both run the Bifröst and travel through it we could have both avoided this trying experience."

"It's not been that bad," she said. "You're not nearly as horrible as I thought you were."

"I very much doubt that you have any clear understanding of how horrible I am," he said. "You have a tremendous number of opinions about me given how little you actually know _of _me."

"I read the Prose and Poetic Eddas," she said. "Even if you were kind of a dick at times you were still my favourite. The bit where you turn up at the feast and call everyone an asshole was by far the best part of the whole thing. Plus, Thor comes off as a complete imbecile in them – he literally eats everything, all the time, and then kills anything he doesn't eat – and he turned out to be alright."

"In some respects I don't think I've improved your intelligence at all." He looked incredulous, although slightly less irritated than he usually was when Thor's name came up.

"I think spending time with you has made me immune to being called stupid," she said.

"I shall endeavour to make my insults more effective."

"Don't be a dick, Loki."

…

"That," said Tony, looking down at her equations with a hint of awe, "is _genius_."

"It fits," Darcy said, tapping the paper with her pencil. "It's the only thing that fits."

"When we get this thing built I'm taking you back to Stark Industries," he said. "I could use someone like you in our R&D department. You'd love it – great benefits, the world is your oyster, all that jazz."

"Can Jane come too? These are _her _ideas, originally."

She was certain she didn't imagine the hesitation before he replied. "Sure."

"C'mon," he said, picking up bits and pieces of cannibalized electronics and tossing them back onto the table. "Let's see if we can build this thing."

…

Talking with Tony Stark was about as close as Darcy got to her conversations with Loki with another human being. As they talked she felt the air around them buzz with potential energy, practically calling her to transmute it to fit the equations they were discussing. To use it to build; to wield it.

_Magic and science: where I come from they are one and the same_.

While she knew Jane shared her passion, and her burning desire to understand everything, Tony was able to _match _it.

Until she mentioned a recent article published in the _Indian Journal of Mathematics and Mathematical Sciences_.

"Sorry," he said. "Don't speak Hindi."

"What do you speak?"

"Bit of French, some German. Languages aren't really my thing." He looked up from the piece of metal he was welding. "Didn't know you spoke Hindi."

"I taught myself," she said. "You should learn."

"Haven't got the time," he replied. "You can get by with English in just about any field nowadays anyway."

Yes, she thought, but why would you want to just 'get by'?

…

"The paths are just energy," Loki was saying. "You can see them if you know how to look."

He stood behind her, close enough that she could feel the faint prickle of his body heat on her back and the contrast it made with the cool night air on her front – but he was careful not to touch her.

"Start small – see a path between here and the end of the road in the distance. Find the path that the energy takes between that spot and here, and will yourself there."

"Can I will myself inside?" she mumbled, wishing she'd brought a sweater.

"Focus," he said. "We are running out of time."

"Says who?" she muttered. But she stared at the end of the road, where it gave way to barren desert sands. She wondered why it just stopped pointlessly in the middle of nowhere.

"Focus," he said again, sharply.

"Sorry." She closed her eyes, and then opened them again, staring at the spot, willing herself there as best she could. And then, like a veil was lifted on the world, she saw a path through space, and she latched on to it and was pulled and the breath rushed out of her and suddenly she was stumbling in the dirt and panting. In the distance she could see Loki standing, his arms crossed, staring at her.

She looked around and then burst out laughing.

"Holy fuck," she said. "I can _apperate._"

…

"Can you do that too?" she asked as she and Loki stumbled – well, she stumbled, still heady with excitement at what she had just done, Loki strolled in like he owned the place – into her apartment.

It was spotlessly tidy now – the overwhelming complexity of the inside of her mind had lead to a necessity of creating order in the world around her. Loki had been pleased – although his tendency to reorganize her bookshelf in alphabetical order by title rather than author's name, as she preferred, was starting to drive her absolutely bananas.

He looked at her in irritation. "Of course I can. I assure you, there is nothing that you are capable of that I cannot also do."

"Oh, yeah?" she said. "Can you do this?" She touched her tongue to her nose.

He stared at her blankly a moment, before carefully sticking his tongue out and curling it up towards his nose. It was at least two centimetres short.

She burst out laughing, falling back to the bed, and she was surprised to see him do the same beside her.

"I amend my statement," he said, looking up at her ceiling. "There is nothing of consequence that you are capable of that I cannot also do."

She poked his thigh with her foot. "Ha!"

He looked affronted. So much like a cat.

"So if you can do that, how come you can't poof home?" she asked, stretching her arms above her head. His eyes watched as the hemline of her shirt rode up, exposing a sliver of pale skin around her stomach.

"Ordinarily I would," he said, shaking his head slightly and looking at the far wall. "However these are extenuating circumstances."

"Extenuating how?"

He looked contemplative and very serious. "Traveling between realms by such means requires traversing the space between the realms without the protection of the Bifröst. There are beings that dwell between the realms – I should not like to be seen by them now."

She shivered slightly, and sat up, pulling her legs in and resting her chin on her knees. "What kind of beings?"

"The sort that would challenge me for the title of monster, and win," he said softly.

"You're not a monster," Darcy said. "You're my friend."

He looked at her in surprise and she saw his adam's apple rise and fall as he swallowed. "One does not preclude the other," he said finally. "And it is unwise to call me 'friend'."

"Who said I was wise?" she said.

He laughed at that, although Darcy thought it sounded sad.

…

"What happens when you go home?" He was sprawled out on her bed reading Machiavelli's _Il Principe_, which she'd jokingly suggested earlier in the week and then been slightly horrified to discover he'd actually taken her up on. His shoes lay discarded on the floor, although they were tucked neatly side by side, and he looked surprisingly like he belonged there – with her.

"Nothing good, I expect," he said, pointedly turning a page. He managed to do so obnoxiously loudly and ostentatiously.

"So why go back?" She crossed her legs at the ankles and rested them on the corner of her desk, pushing her chair back to balance on only the back legs.

"If you fall over and break your neck from abusing your furniture in that manner, I will do nothing to help you," he said, turning another page.

"Nobody reads that fast," she said, pointedly leaning even further back in the chair. "Not even me. And I'm probably the fastest reader ever."

She wobbled and had to grab the side of the desk in support. He smirked at her over the top of the book.

"You shouldn't leave," she said. "I'm not sure anyone in Asgard knows how to properly irritate you. You'll be bored within a week."

He snorted. "Never was a more erroneous statement spoken."

"Oh, I'm sure they irritate you," she said. "I've met Thor, remember? I just doubt they irritate you _properly_."

He let the book fall onto the bed and looked at her in amusement. "How, precisely, does one irritate me 'properly'?"

She sniggered and deliberately let her chair tip backwards. She managed to roll out of it, inelegantly but effectively, as it hit the floor.

He picked up his book again, but she could see he was smiling.

"You could at least help me up," she said.

…

The following morning she woke up with a splitting headache. She stumbled to the bathroom and threw up, before crawling back into bed, pulling the covers over her head.

…

She thumbed through her Teach Yourself Arabic book. She'd read it yesterday, but couldn't remember the vocabulary she'd learned.

She read them again, and then covered the English translations, quizzing herself.

She got seven out of thirteen correct.

Her head throbbed painfully.

Something was wrong.


	4. Decline

**Note:** The M rating applies to this chapter. Consider yourself warned. :)

**Chapter 4: Decline**

* * *

She started writing everything down. She wrote up a paper on her work on creating the Bifröst, and wrote two more based off the notes she'd made from the articles she'd read.

She typed up a journal, detailing comprehensively the reading she'd done, her critiques, improvements and thoughts. She went back to one of the articles – the one she'd mentioned to Tony, in Hindi on Gauss-Bonnet gravity and the possibility of wormholes without exotic matter – to check a point she couldn't quite recall, and found it took her half an hour to read the page. She'd had to check the dictionary several times. Last time she'd read it, she'd been completely fluent, and the words had come to her as easily as English.

She began writing everything down.

…

_I have begun to lose things: skills, memories_. _But I think above all I have begun to lose pieces of myself. I wake up every morning feeling a little less whole, although I am never sure exactly what I've lost._

_It scares me._

…

"It's complete, I think," said Jane.

Tony was still fiddling.

"It'll work," she said. "I know it will."

Erik wrapped a paternal arm around her shoulder and gave her a fond smile. Coulson watched casually from the far side of the room. "Pleased to hear it," he said. "We'll test on Thursday."

Jane shot him an irritated look and Tony gave him the finger, but he ignored both with the air of longsuffering practice.

"If this works we'll be sure to get a Nobel prize!" Jane was beaming, and practically jumping up and down with excitement.

"When," said Tony. "When it works."

"You sound awfully sure," Darcy said, passing him a screwdriver as he made final adjustments to the first Earth Bifröst.

"It'll work – I helped build it."

Darcy snorted and Jane rolled her eyes, but she did flash Darcy a small but genuine smile over the top of the machine. Darcy smiled back brightly.

"Congratulations, Jane," she said.

…

"We need to make our attempt tonight," Loki said. "Before SHIELD attempts to test the device."

"The lab is under guard," she said. "We can't get in."

"I assure you, I am more than capable of slipping past a handful of mortal flunkies," he said, sounding affronted.

"Who taught you the word 'flunkies'?"

He frowned, ignoring her and looking down at her desk. He pulled a purple sticky note off the surface. "What is this?"

"To do list," she said.

"Why do you have one?"

"To remind me of things I need to do," she said, flatly.

He stared at her as she looked studiously at the ground. "Something has changed," he said at last.

"I'm forgetting things," she said softly. "I've lost two languages, and I'm not sure I understand all my notes anymore. I was staring at the equations I'd written for hours yesterday and I didn't fully understand what they meant."

He placed the post-it note back on the desk.

"It doesn't matter," she said. "You're going home tonight anyway."

"It… matters," he said. Her heart swelled with an undefined, and dangerous feeling.

…

Sure enough, Loki managed to do something to the SHIELD guards surrounding the lab, which allowed them to walk right in without anyone noticing. When she asked what, precisely, he'd done, he'd simply looked at her in concern and told her to figure it out herself.

She wasn't sure how.

He fiddled with the Bifröst machine, looking for all the world like a fussy mother, making one last final check to ensure everything was presentable.

"When the energy gathers, you will need to direct it," he said.

"I know."

"It will be alright, Darcy," he said.

She blinked. "I don't think you've ever said my name before. Not sure that's a good sign, to be honest."

He grinned.

"Ready?" she asked, her hand hovering over the switch.

"Do your people have any blessings for travelers?" he asked.

"You're a _god _and you want a blessing?" she asked sceptically, shrugging one shoulder. "My gran had one she used to say to us, I guess: 'may god stand between you and harm, in all the dark places where you must walk.' Always seemed a bit melodramatic for a car trip home, but it's the best I've got."

He looked at her seriously, though she could see a faint twinkle of amusement in his eyes. "Let us hope that I will have no need to walk in dark places," he said.

"Sure thing, dude." With a deep breath, she flicked the on switch, and the machine hummed as it came to life. "Let's get this show on the road."

…

For a blinding moment she saw the universe – the trunk of the world's tree binding together all the realms that clung to its branches. Her mind soared through the towers of Asgard, with its golden halls lit by flickering candlelight that made the shadows dance, through the open fields of Vanaheim to the cold, ruined ice palaces of Jotenheim. She focused on Asgard, directing the energy in the room towards the branch that wound its way towards the heavens, and she heard what sounded like footsteps as she sensed Loki step upon it. And for one, long, precious moment, Darcy Lewis was transcendent.

It crumbled, and the veil fell. Yggdrasil's branches covered the stars in darkness and she lost the path – she lost _Loki_. She stumbled backwards as she heard the SHIELD guards, no longer unaware of her presence, come crashing through the door. The energy of the Bifröst scattered, directionless through the room.

Loki was gone.

…

"Why did you turn on the Bifröst prototype by yourself?"

She stared blankly at the floor in front of her.

"Was someone here with you tonight?" Coulson's voice was deceptively calm, but she wasn't foolish enough to think that he wasn't angry. "Did someone ask you or compel you to turn on the Bifröst prototype?"

Even though he was gone she still couldn't speak his name.

…

Coulson let her go home the next morning, although he made it abundantly clear that her home was going to be monitored, and her movements tracked.

She'd expected as much. What she didn't expect was to walk through the door and find Loki sitting on her bed.

"I confess," he said, as if he hadn't just returned from the dead, "I had expected you back last night. I'm afraid I finished off the last of your poptarts in your absence, and in the absence of any _actual food _in your apartment."

"I thought you were _dead_," she said, leaning against the door and feeling as though her legs were about to give out any second. "I thought I'd _killed you_."

"Ah," he said. "No. But a regrettable mistake has been made, and I am beginning to suspect that it may have been my fault, which is tremendously irritating."

"Shut up," she said. "I thought you were _dead._"

"Darcy," he said, placatingly, rising from the bed and walking towards her. "I am not dead.

"I thought you _were_." She leaned forward until her forehead rested just below his collarbone, and her arms wrapped tightly around his waist. He rested one hand lightly on the back of her head and held her like that until she stopped shaking.

"I must congratulate you," he said, and she felt the vibrations of his voice against her cheek. "I have lived for more than a millennia, and I don't believe anyone has ever been so pleased to see me before."

"That's because you're a jerk," she said.

"No doubt."

…

"If you will recall," he said, when she'd finally let go of him and they'd both settled into their usual positions sitting on opposite ends of her bed. "I have the ability to travel without a Bifröst if necessary. When the bridge collapsed, I was able to bring myself back here – although not fast enough. I was seen."

"By whatever lives between the realms?"

He nodded. "I cannot speak his name," he said. "Names have power, and he would be able to find me if I did so, although he likely already knows where I am." He straightened his cuffs, something Darcy now recognized as a nervous habit. "He is coming."

"When?" she asked.

"Soon."

"Why did the bridge collapse? Why am I forgetting the things I've learned? I could _do it_, I _saw_– "

He reached out and laid a hand gently on her temple, the same place he'd touched the first time they'd met. "I have expanded your mind beyond the frontiers of its design," he said, surprisingly softly. "It is contracting. I – I should have anticipated this."

"But you didn't," she said. "So, you have no idea how quickly or how far my mind will… contract."

"No," he said.

"I can't teleport anymore," she said.

He made a non-committal noise and looked resolutely at the wall on the far side of the room.

"I also can't speak read French very well, or Hindi, Mandarin or Latin at all," she said. "Although as far as party tricks go, the teleporting was a much bigger loss. Latin is never cool at parties."

She pulled her knees up to her chest and shivered. He sat so still that he hardly seemed to breathe, staring at nothing at all. Or, at least, nothing that she could see.

"Are you going to poof yourself to Asgard, then?"

"No," he replied. "The Chitauri will be coming. I will offer what defense I can."

"Oh," she said. "Can I do anything?"

He frowned. "Your part to play in this is over, I think."

Her heart sunk with the realization that he was likely right.

"But I want to do something to try and stop this," she said. "Research on reversing whatever it was you did to me."

He nodded after a moment's consideration. "Of course. I will try to bring you what you need."

…

She felt doors closing on possibilities all around her. The loss of her capacity to learn bothered her more than the loss of knowledge. Journals she used to read for pleasure became something she read as a chore to keep the pretense that her mind still was as it had been before. She spent more than three hours re-reading an article from the _Physical Review_without understanding it. Her mind stopped asking so many questions about the things she read, and she wondered what they would have been and whether she would have been able to figure out the answers.

She threw her notebook at the wall in frustration and screamed into her pillow until she couldn't scream anymore.

…

He found her sitting on the floor with a copy of _Paradise Lost_.

"I remember that I loved this poem," she said, without looking up. "Now I'm not sure I understand it. And I think I definitely hate it."

He plucked the book out of her hands and placed it on the desk. Then he dropped to his knees and kissed her so hard their teeth clacked together.

She kissed back, and tugged at the jacket of his suit as his hands tangled in her hair and pulled, almost too hard and she bit at his lower lip as he brought both her wrists together and held them with one hand pinning them to the bed above her head and she arched into him and for one moment they fit together perfectly, like two halves of a whole –

Then they were pulling and pushing at each other again, slipping hands under clothing to find hidden skin, as he lifted her onto the bed and out of her skirt, and she pulled his shirt over his head, his hands getting caught in the cuffs and she giggled and tugged hard enough that the buttons popped off. She ran her hands over every bit of him that she could reach, memorizing by touch and holding on to it for as long as she could before it drifted away.

She rolled them both, and they nearly toppled off the bed, but Loki was dextrous enough to catch her and settle her in his lap. Their kisses were deeper now, less frantic but no less passionate, and his hand rubbed sensuously at her nipple while the other settled on her backside and pulled her even closer to his body.

She moaned as he trailed open-mouthed kisses down her neck, and between her breasts, finally catching one nipple in his mouth and flicking it with his tongue in a rhythm that matched the one her hips had set as they ground down on him. Her fingers tangled in his hair and her nails scratched up his back and she felt him shiver.

He rolled her onto her back and she caught a glimpse of his grin before he rocked back onto his heels and pulled her panties down and off, tossing them across the room where they caught on the corner of her bookshelf. He hooked one leg over his shoulder, trailing kisses up the inside of her thigh, and her hips rose up off the bed almost of their own accord. She reached down to rest a hand on his head, tangling her fingers in his hair, and he licked a long, warm, wet line along her cunt, teasing her clit with his tongue. Her back arched, and she bit down on her first two fingers to stifle a moan.

Gently, he worked one of his long, slender fingers into her body as his tongue flicked rhythmically over her clit.

His name fell from her lips like a prayer, over and over, like supplication, as her muscles tightened around his fingers and she came, shuddering and crying his name. He leaned over her, and when she kissed him she could taste herself on his lips.

She wrapped her legs around his hips, and he dropped his head to her shoulder, nipping gently at her clavicle as she guided him into her body. His hand reached up to entwine his fingers with hers, and he began to move, and she made a point of kissing every inch of him she could reach and pulling him so close that when he came his lips were pressed against her temple and she caught her own name as he whispered it quietly against her skin.

…

"I saw Asgard," she said, later, her head tucked under his chin as her fingers trailed mindless patterns across his skin. "When I was directing the Bifröst. It was beautiful."

"Appearances can be deceiving," he said.

"You're always so grumpy."

"I brought you reading material," he said, choosing to ignore her observation. "The spell I used was relatively obscure, but what little information existed on it within the libraries of Asgard is now at your disposal."

She sat up and twisted around to look at him. "You… brought me _space books_. Books from _outer space_. About _magic_."

He raised an eyebrow in a familiar expression designed to indicate that he thought she was completely off her rocker.

"Magic space books!" she giggled, and then bent down to kiss him slowly and deeply. "Best. Gift. Ever."

"I had no idea," said Loki, "that you were so easily bought."

…

Thor turned up the next day, and the SHIELD agents posted outside her house knocked on the door and then frog marched her out of the house and up to the lab. Jane was standing so close to him she looked like she wanted to hold on to him and make sure he stayed put, but wasn't quite willing to admit it. He was examining the Bifröst prototype and talking to Tony Stark.

"Darcy!" Jane said, when she caught sight of her.

Thor turned, and looked at her, looking unusually grave. "Darcy," he said. "Heimdall caught sight of you when the Bifröst was opened. He said you had been working with Loki."

And just like that, the cat was out of the bag. Surprisingly, it was Erik who started shouting first.

What ended the argument – Coulson and Erik were insisting emphatically that Loki was dangerous, and Jane and Tony were insisting equally emphatically that Darcy _wasn't, _with interruptions from Thor in the form of bellows of indignation any time anyone said anything that he considered a slight upon his brother's honour – was the arrival of Loki himself, who casually strolled into the lab and leaned on the table behind Darcy.

Everyone slowly stopped talking and turned to stare. Loki managed to ignore all of them at once.

"Brother," said Thor, his voice thick with emotion. "We had thought you dead."

"You have _got _to stop doing that to people," said Darcy.

Loki ignored her too. "You have come alone?"

Thor frowned. "I came to find you. You were hidden from Heimdall's sight until you set foot upon the Bifröst. When he saw you and told us you were alive, I came at once."

"This world is in peril," Loki said. "The Chitauri plan to invade – they are lead by a formidable force. They too caught sight of me during the mishap with the Bifröst. They are coming, and soon. Will Asgard give aid?"

"I have offered my sworn protection to this realm," Thor replied. "But without a Bifröst we cannot bring a defence force here – sending me alone was already a tax on our father's strength."

"_Your _father," said Loki acidly. "Without aid, then, we must make ready our defences."

"Gentlemen," interjected Coulson, stepping between the two Aesir smoothly, "who, precisely, are the Chitauri?"

…

"I don't understand," said Jane, after Thor and Loki had been lead away by Coulson under the threat of a debriefing, "why the Bifröst didn't work when you tried it with Loki. Our calculations were correct."

"It needs a mind to direct it," Darcy replied, stirring sugar into her coffee. "It harnesses energy fine, but without conscious direction that's all it does."

"How do you direct then energy then?" Tony asked, looking at her speculatively.

"I can't remember," she said, shrugging. "It's all slipping away from me. I can't understand my own notes, the things we worked on…"

"Oh, _Darcy_," said Jane, placing a hand on her shoulder.

"Well, I couldn't even understand half your notes by the end of it," added Tony. "So that's hardly a sign you're dumb as a doornail."

"Not yet, anyway," Darcy said gloomily, and she tried to ignore the way Tony was staring at her intently.

"But it was Loki who did this to you, right? Who made you… the way you are?" Jane asked tentatively.

"Yep. He needed someone to drive his Bifröst, or whatever." She took a long drink of coffee. "I don't think he intended for it to regress like this. He's been… kind."

Tony's speculative look intensified. "I hope 'drive his Bifröst' isn't a euphemism."

She tried not to blush.

* * *

**Footnotes:**

(1) The line 'may God stand between you and harm in all the dark places where you must walk' comes from Babylon 5. JMS credits it as an 'Egyptian prayer', but a cursory search couldn't provide me with the provenance of the original so it may be his work, or, at least, his translation.


	5. Quietus

**Chapter 5: Quietus**

They were moved to New York, and Tony offered her a room in Stark Tower. She didn't see much of anyone except Jane, who stopped by daily despite being busy working with SHIELD's technicians.

She read the books Loki had brought from Asgard, pouring over them in the hope that she might see a means of reversal. Two were in All-Speak, which was as comprehensible as English. One was in Old Norse. She read through it once, with a dictionary, but she couldn't keep the cases straight, and it took forever for her to look the strong nouns up in the dictionary because of their forms. She tossed the book aside and focused on the other two, but she could no longer feel the energy in the world around her, or see it to manipulate it, and without that the spell was just words.

She tucked the books away in the back of her dresser, walked out of Stark Tower and kept walking until the sun went down and Loki turned up wordlessly to walk her back home. He dressed her in pajamas like she was a child, but she was too tired, _too empty_, to care, and she let him hold her until she fell asleep.

…

Later that same week, when Dummy tried to use the blender without putting the lid on and got smoothie all over the ceiling of the kitchen she laughed almost until she cried, until she saw Loki standing in the corner and she caught the way his face fell before his expression closed off. She shut herself in her room and spent the rest of the day trying to read _Moby Dick_, but she kept getting bored and skipping things and then needing to go back because she'd lost what was going on until she finally gave up and threw the book at the wall in frustration. When he came by in the evening he picked the book up off the floor and placed it on the bookshelf, but he didn't comment.

That evening he kissed her like he was trying to tell her something and fucked her slowly, but she couldn't understand what he meant and she didn't have the heart to say so. She felt like her half of the conversation was missing, and that there was something important she ought to be telling him, but she didn't know what.

In the end she said nothing and just clung to him until he gently pried her hands away and kissed her goodbye.

"Come back soon," she said.

"I will," he said, but he looked as lost as she felt.

…

_I'm scared I don't have much time left with Loki before I become too stupid for him to put up with._

…

Two weeks later, Loki was on television, and he looked really cool. He was with Thor, and Tony, who was wearing his Iron Man suit, a giant green monster man, a guy in an American flag suit and two more people, but she didn't know who they were. They were fighting aliens. Jane made her go to the basement to hide, because the aliens were outside.

"It's Thor! It's Thor, Jane!"

"I see him." Jane held Darcy's hand tightly, and Darcy hid behind her during the scary parts. On the TV, Loki blasted a bunch of aliens with his magic, and Darcy started cheering. Jane just held her hand tighter, and wrapped her other arm around Darcy's shoulders, pulling her in close.

…

No one will tell her exactly what happened, but she knows they won. Jane took her back upstairs, and Thor and Loki were there, and so was Tony and he was wearing his suit, and the American flag man was there, whose actual name was Steve Rogers, and the two others, who were called Clint and Natasha, and they were _assassins_, and another guy who looked really tired. Jane said he was actually the big green monster, but Darcy thought she was probably kidding.

She got to meet everyone, and Steve Rogers was very nice to her, and everyone said hello except Loki, who stood at the back and stared out the window. It was rude, and she told him so, but she said it was ok because he was still her favourite. She gave him a big hug because he looked like he needed one, and she told him that he was the best friend she'd ever had.

He looked really upset after that, and then Tony took her downstairs to meet Dummy, the robot that he'd built. He also made the house talk to her and it was named JARVIS and she told him that he was her third best friend after Loki and Jane. Thor asked why he wasn't third, and she told him it was because he didn't have a talking house. _Duh._

"Tell Loki I'm sorry I made him sad, ok, Thor?"

"I will tell him, Darcy," said Thor seriously, and he looked sad too.

…

_I don't know how to make people happy. Jane says it's not my job, but I want to._

…

Jane sat with her every day, and she would read books. Darcy found them really boring, especially the ones about stupid things like elves and hobbits and magic rings because elves and hobbits and magic rings didn't exist.

All the buildings outside her window were broken.

"They were broken in the fight," said Jane.

"Must've been pretty big."

"Yes," Jane said. "Yes, it was."

"Are they gonna build them back again?" Darcy asked.

"Yeah, they are."

"Good," she said. "I don't like it when they're broken."

…

Erik came in with Jane the next day and he made her take a test. He said it would tell how smart she was. He said he would time two hours and she could answer as many questions as she could before he said stop.

She didn't understand most of them, so she guessed some answers and left some of them blank. She drew a smiley face at the end like her teacher used to put on her schoolwork when it was good so that hopefully he'd think she was smart.

"Did I do it good?" she asked him as he looked at her answers.

"You did really well, Darcy," he said. "Really well."

"What did she get?" Jane asked, taking the paper out of Erik's hand.

"55," he said.

"That's more than halfway to one hundred," said Darcy, and she smiled.

…

Loki came by once. He sat very still for a long time in the chair and she watched him wondering if it was a game and if she should be quiet and still too. She wasn't very good at it, because sitting still made her legs itch.

Finally, he got up and sat down beside her.

"I will find a way to fix this," he said as he held her face between his hands. "I will come back."

"Don't go," she said, holding on to his hand. "I don't want you to go."

He kissed the top of her head before he left, and she cried all night even though she wasn't sure why she felt so empty and alone when Jane was there stroking her hair. He didn't come back the next day, or the day after. The day after that she'd forgotten to ask if he was there in the morning.

…

Erik brought a doctor who made her look at ink blots and tell him what she saw.

She saw ink blots.

He put them away and shook his head and then talked to Jane and Erik in the hallway for a long time in a low serious voice.

"Did I do it wrong?" she asked Jane when the doctor was gone.

"You did fine," said Jane.

…

Loki came into her room in the middle of the night. His hair was sticking up at the back and he looked really tired, like he'd been running a lot, and hadn't slept for a week. He made her eat an apple and it had golden skin and it tasted funny, like tingles, and made her belly all warm inside. She tried to make him eat a piece too because he looked really tired but he said it was a special apple just for her and that it would help her get better. He told her it had come all the way from Asgard, and that she shouldn't tell anyone he gave it to her because it was a secret.

She remembered to say thank you for the present.

When she woke up Loki and Thor were shouting about apples in the hallway. Thor shouted that Loki had stolen the apple. It felt heavy in her stomach and she refused to eat any breakfast.

…

Erik wanted her to take another test, but she was tired of tests and she'd already taken one. Everyone else was talking in hushed voices, and she heard her name more than once. She coloured in the geometric shapes on the test with her pencil and tried to stay inside the lines.

"What good will testing her again do, Erik? If there has been improvement, it's negligible. She can barely tie her own shoe laces for god's sake," Jane said, and they all turned to look at her.

"I'm sorry, Darcy," said Jane, though Darcy didn't know what she was sorry for.

Darcy smiled as big as she could, and Loki walked out the room and slammed the door so hard it cracked. Jane started crying, so Darcy hugged her tight because she wasn't sure what else to do.

…

Thor and Loki were shouting about her in the corridor again.

She put a pillow over her head and hummed _Au Clair de la Lune _until JARVIS the house turned on music for her.

"Thank you JARVIS house," she said.

"You are most welcome, Miss Lewis."

…

"Listen carefully, Darcy, this is important," Loki said. He was holding her hands really tightly and she squirmed a bit hoping he'd let go. "I am going to erase your mind as it is now, and then bring it back using the memory of your mind the way it was the night we first met, do you remember?"

"No," she said.

He sighed and squeezed her hands tighter.

"I'm going to try and make you like you were before," he said.

"Smarter?" she asked. She didn't remember before. She knew there were lots of things missing, and that she had been smart before. She knew that she'd helped make a machine. Tony had let her see it. She didn't know what it did or how it worked, but she was proud that she'd helped.

"Yes," he said.

"So I can build more machines?" she asked. "Like Tony and Jane?"

"If that's what you'd like to spend your time on, yes, I suppose."

"Is it gonna hurt?"

He looked very sad. "Possibly. And it may not work at all, Darcy. It is possible that you might not wake up."

"But you're going to do it, right?"

"Yes," he said, and his hands squeezed her so hard it pinched.

"It'll be ok," she said. "I trust you."

He let go of her hands and grabbed the back of her head, gently pulling her towards his chest. She felt his nose in her hair and his breath tickled. "Don't cry," she said, wrapping her arms around him tight as she could. "It's ok." She said it over and over, "it's ok, it's ok, don't cry, it's ok," until he stopped shaking. "Don't be scared," she said. "I'm here. It's ok."

…

Everyone came in to say good luck to her. She told them she didn't need it, because Loki was going to do it and he was really smart.

"I wouldn't be so damn sure of that, kiddo," said Tony.

"You're smart too," she said, patting his hand comfortingly. "And soon I will be too."

When he left, Loki and Thor came in together and Loki made her sit on the edge of the bed.

"When I wake up and I'm smart, I'll build you both a machine even cooler than JARVIS house," she said.

Loki smiled but it didn't reach his eyes. "I look forward to it," he said.

He reached out and put his hands on her head, gently at first but then he squeezed until it hurt. She told him to stop but instead Thor held her still until she fell asleep.

…

_JARVIS house, please promise to give all my books to Jane if I don't wake up smart. She likes books, and I can't read them._

…

She felt like she had the world's worst hangover. Her head was pounding, and her arms ached. She was debating the relative merits of pulling the covers over her head or making a mad dash to the bathroom to hurl when she heard someone move beside her.

She opened her eyes blearily, and blinked as someone huge and blond came into focus. "Thor?" she asked, groggily.

"Darcy!" he said exuberantly, and she winced as her ears rang and her head pounded.

"Keep it down, man, I think my ears are bleeding."

"My apologies," he said, more softly. "How do you feel?"

"I think I'm dying," she said. "What the hell _happened_ last night? When did you get here? And where _is _here exactly?"

"What do you remember?"

"Uh, working on building an Einstein-Rosen bridge with Jane." She rubbed the heels of her palms into her eyes, and then rubbed them in circles on her temples.

"Seriously, when did you get here? Last night?" She squinted up at him.

"I have been here many weeks," he said, looking cagey. He glanced across her to the far side of the room, and she followed his gaze and jumped a bit to see another person leaning against the wall on the far side of the room. He was dressed much like Thor and the other Asgardians she'd met, with a lot of leather and metal and a cape – dear god, a _cape_ – all she could ever think of when she saw that cape on Thor was the super hero costume lady from _The_ _Incredibles _and her warnings about jet engines – although she was sure she hadn't seen him before.

"Geez," she said, pressing her hands into her temples. "You scared me."

"It was not intentional," he said. "Are you experiencing any side effects?"

"Side effects of what?" she asked. "Does the splitting headache I have count?"

The corner of his mouth twitched slightly. "Likely, although prolonged exposure to Thor can also result in similar effects."

Thor made a wordless noise of protest, which seemed to only further amuse her guest.

"Right," she said. "So, _again_, side effects of what? And, sorry, who are you?"

It seemed like entirely the wrong thing to have said. As soon as the words left her mouth his entire expression shut down, and he straightened stiffly, turned and walked out of the room, shutting the door firmly behind him.

"Was it something I said?"


	6. Epilogue: Renascence

**Chapter 6: Renascence**

Tony Stark, _genius, billionaire, playboy, philanthropist _extraordinaire, who she'd apparently worked with, impressed and couldn't recall meeting, gave her a warm, slightly-too-long hug when she saw him.

"Good to see you looking more yourself," he said, grinning.

"Uh, thanks," she replied. "Nice, uh, house. Thanks for letting me stay in it."

"Least I could do," he said. He handed her a plain manila folder, which was nearly overfull with papers. "Here," he said, "I had Pepper round everything of yours up. Figured you'd have questions. They're your notes from the past six months."

"Thanks," she said again.

"Let me know if you need anything explained," he said, over his shoulder as he started to walk away.

She very nearly called out 'how about _everything_?'

…

Jane kept asking her how she was doing. It was almost as unnerving as the way Steve Rogers stared at her like she'd grown a second head every time she spoke to him, and Thor grinned widely every time she walked into a room. At least Steve had the decency to look abashed at his tremendous awkwardness.

She watched news footage of the city being destroyed, and thought it looked like it had been done with CGI because nothing that catastrophic ever looks like it's really happening. But the city was still full of half-ruined buildings.

She saw no sign of Loki at all.

…

Thor had explained the rough outline to her: that she'd been made into a super genius by his brother to run a Bifröst, and that it had backfired and she'd regressed to something like a child in the body of an adult, and that somewhere along the way, although no one seemed to know any details, Loki had become 'attached' (to use Thor's word for it) enough to her, to steal one of the apples of Idunn for her, and to scour the nine realms to find a way to reverse the spell.

Which, if you asked Darcy, was really the bare minimum he could have done given he was the one who'd got her in the situation in the first place. But apparently nicking the golden apples was a Really Big Deal. Thor had explained that not only was her body physically more durable than a normal human being, but she could also expect a much longer lifespan – although not immortality unless she got more apples.

This information had been filed in her brain under _'Things She Was Not Ready to Deal With_'.

…

Most of her notes made no sense to her. It was like reading the work of a stranger – a brilliant stranger, with her handwriting. She found notes scribbled in over a dozen languages, with equations mixed in.

There were well over twenty drawings of what she assumed was Yggdrasil, the space between the branches filled with equations, representations of what she took to be wormholes, multi-dimensional polynomials and Norse runes.

She hung the largest one of them up on her wall. She wasn't sure if it was a testament to her achievements, or a reminder that the greatest would ever be was gone even from her memory.

At about halfway through the file she began to see the downward slide, and the equations, notations and citations became intermixed with more personal messages.

_I do not know what frightens me more: that I cannot remember what I've lost, or that I won't remember what I know._

_Jane pities me. So does Loki. Sometimes I hate them both for it._

She carefully put everything back in the folder and put it in the back of her dresser, tucked away. There were already three books back there, and she perused them curiously. _Spellbooks_. She left the two in English on her bedside table and put the one in Norse back in the drawer.

…

"Tell your brother to come out of hiding," she said to Thor over breakfast. "I want to talk to him."

He looked a bit surprised, but nodded in agreement anyway. "As you wish."

…

She made coffee for Jane and Erik in the lab where Tony had set them up. "I assume since I've been out of commission you've got a backlog of data entry for me to get through, huh?" she said, switching on the laptop without waiting for a reply.

Jane grinned at her and tossed her a file with all of her notes.

"God," Darcy said, "if there's one thing I really wish I _could _forget, it's your handwriting, Jane. I see it hasn't improved in my absence."

"We've got to give you something to do to keep you out of trouble," said Erik.

…

He knocked on her door that evening. She'd been expecting Jane, so she blinked and started slightly when she found six feet of leather-clad, lanky Asgardian on the other side of her door.

"Thor said you wished to speak with me," he said.

"Uh, yeah," she said, feeling out of sorts and tremendously awkward. "Uh, come in, I guess."

He looked around the room, his gaze lingering on the books on her bedside table for a moment longer than anything else.

"I have some questions that I was hoping you could answer," she said, sitting down at the desk.

He leaned up against the rail of her bed with his hip. "I had surmised as much."

"Great," she said, biting down hard on the sarcasm she so desperately wanted to throw at him. "Were we… uh… would you say we were… friends?"

"I believe you did throw that word in my direction, yes," he said, sounding somewhat nonplussed by the idea.

"And what words did you throw in _my _direction?"

She could see the muscles in his throat work as he swallowed from where she was sitting. "I have no intention of holding you to any implied agreement about the nature of our… association… that you do not recall making," he said. "Since you have, by your recollection, only met me once, I very much doubt that we are 'friends'."

She could _hear _the air quotes around the word 'friends'.

"But we _were_," she said. "So I don't see why we couldn't be again."

His eyebrows raised and he blinked in surprise. "You are aware," he drawled, "that I am the person responsible for the fact that you can no longer remember the last six months of your life, and that you very nearly spent the rest of that life with the mind of an imbecile."

"Yes," she said. "I'm also aware that you're the person who managed to find a way to reverse what had been done, that the damage was not done intentionally and that you stole one of the super special one-bite-from-me-and-you'll-live-forever apples from Asgard, which based on the way Thor told it, sounds like a _huge no-no_, all in a bid to fix me." She shrugged. "As far as I'm concerned, we're even."

He seemed to sputter a bit before he managed to get any words out. "You _foolish_ girl, we are by _no means _even – I nearly _killed _you."

"Key word in that sentence is 'nearly', I think. Besides," she said, standing up and walking to the dresser, digging out the file with all her notes. "There's a whole notebook page in here where I wax poetic about how amazing you are for bringing me _space books_– I'm not sure what that means and I'm kinda hoping it's not a euphemism." He looked torn between screaming at her and bursting out laughing. "Anyway," she continued, "I was, however briefly, by all accounts the smartest human being in the world there for a bit, and I seemed to find plenty worthwhile in you. So, I figured I'd take some of my own implicit advice."

She reached out her hand towards him, palm up. "Friends?"

He stared at it for a long, awkward moment before taking her hand in his own. "Friends, then," he said.

"Cool. Now show me your space books, man. I gotta know."

He grinned at her, and it lit up his whole face. Her heart fluttered as her hand reflexively clenched around his, and suddenly, irrationally, hoped that _space book_ actually _was _a euphemism for something.

**Finis.**


End file.
